North Korean power and protocol on show in the South

The interplay between protocol and power was put on show when North Korean leader Kim Jong Un's sister and the country's ceremonial head of state arrived in the South Friday on a historic trip.

As president of the presidium of the Supreme People's Assembly, Kim Yong Nam, who turns 90 this month, is technically the highest-level Northern official ever to visit the South.

But Kim Yo Jong, believed to be 30, has her brother's ear and is believed to be among his closest confidantes, an increasingly influential figure in Pyongyang.

When they were greeted by the South's unification minister in an airport reception room, the older diplomat sought to defer to his young colleague, motioning to her to sit down first.

Grinning, she returned the gesture, and the two went back and forth for a few seconds, before they settled on equality and took their seats almost simultaneously -- Kim Yong Nam a fraction ahead.

North Korea's ceremonial head of state Kim Yong Nam (R) and Kim Yo Jong (C), sister of North Korean leader Kim Jong Un, are greeted by South Korea's unification minister Cho Myoung-gyon (L) on their arrival at Incheon airport

-, Dong-A Ilbo/AFP

While he is officially the head of the delegation, many analysts expect Kim Yo Jong to take the lead in discussions with Southern officials, and she was seen talking with Seoul unification minister Cho Myoung-gyon and his deputy.

She is believed to be carrying a personal message from her brother to the South's President Moon Jae-in.

She is the first member of the North's ruling Kim dynasty to set foot in the South since the end of the Korean War in 1953 and media interest in her visit is immense.

A horde of cameras and journalists recorded her every move as she made her way through Incheon airport, closely surrounded by four bodyguards.

She looked relaxed and TV footage showed her smiling constantly, occasionally glancing around at the facilities -- in the manner of someone used to the public spotlight.